# Define here the models for your spider middleware
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/spider-middleware.html

from scrapy import signals
# middleware.py
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from scrapy.http import HtmlResponse

from scrapy import signals
from scrapy.http import HtmlResponse
from selenium import webdriver

# useful for handling different item types with a single interface
from itemadapter import is_item, ItemAdapter
from selenium.webdriver.support.ui import WebDriverWait  
from selenium.webdriver.support import expected_conditions as EC  
from selenium.webdriver.common.by import By  
from selenium.common.exceptions import TimeoutException  
from selenium.webdriver.chrome.options import Options


# wait = WebDriverWait(driver, 10)  # 创建一个等待对象，等待时间不超过10秒  
# element = wait.until(EC.presence_of_element_located((By.ID, 'my-id')))

class TutorialSpiderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, or item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Request or item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info("Spider opened: %s" % spider.name)



# 在middlewares.py文件中设置Selenium的中间件


# class SeleniumMiddleware:
#     @classmethod
#     def from_crawler(cls, crawler):
#         print('-------------------------------------\n'*3)
#         middleware = cls()
#         crawler.signals.connect(middleware.spider_opened, signals.spider_opened)
#         return middleware

#     def process_request(self, request, spider):
#         print('-------------------------------------\n'*3)
#         # 设置 Chrome 无头模式
#         chrome_options = Options()
#         chrome_options.add_argument("--headless")  # 启用无头模式
#         chrome_options.add_argument("--disable-gpu")  # 禁用 GPU 加速
#         driver = webdriver.Chrome(options=chrome_options)
#         driver.get(request.url)
        
#         body = driver.page_source
#         return HtmlResponse(driver.current_url, body=body, encoding='utf-8', request=request)

#     def spider_opened(self, spider):
#         spider.logger.info('Spider opened: %s' % spider.name)
# class SeleniumMiddleware:
#     def __init__(self):
#         chrome_options = Options()
#         chrome_options.add_argument('--headless')  # 无头模式
#         self.driver = webdriver.Chrome(options=chrome_options)

#     def process_request(self, request, spider):
#         self.driver.get(request.url)
#         return HtmlResponse(url=request.url, body=self.driver.page_source, encoding='utf-8')

#     def __del__(self):
#         self.driver.quit()

class TutorialDownloaderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info("Spider opened: %s" % spider.name)
